Urban areas tend to be warmer than the surrounding rural areas. This effect is called the urban heat island. In the first figure, f computes the average increase in nighttime summer temperatures in degrees Celsius at Sky Harbor Airport in Phoenix from 1948 to 1990. In this graph, 1948 is the base year with a zero temperature increase. The rise in urban temperature increased peak demand for electricity. In the second figure, g computes the percent increase in electrical demand for an average nighttime temperature increase of x degrees Celsius.

(a) Evaluate (g ° f)(1975) graphically. 

(b) Interpret (g ° f)(x).

Transcribed Image Text:

Rise in temperature (°C) 3 4 2 5 Increase in demand (%) N W 17 y = g(x) Year 1950 1960 1970 1980 1990 X Rise in temperature (°C) N y = f(x) T 5